Changes terminal modes similarly
to the external stty command. By default, the controlling
terminal is accessed. Other terminals can be accessed by appending “<
/dev/tty...” to the command. (Note that the arguments should not be grouped
into a single argument.)

Requests for status return
it as the result of the command. If no status is requested and the control-ling
terminal is accessed, the previous status of the raw and echo attributes
are returned in a form which can later be used by the command.

For example, the arguments
raw or -cooked put the terminal into raw mode. The arguments -raw or cooked
put the terminal into cooked mode. The arguments echo and -echo put the
terminal into echo and noecho mode respectively.

The following example illustrates
how to temporarily disable echoing. This could be used in otherwise-automatic
scripts to avoid embedding passwords in them.